• Best of luck to the class of 2025 for their HSC exams. You got this!
    Let us know your thoughts on the HSC exams here

Titration calculation problem (1 Viewer)

thebigticket

Member
Joined
Jul 5, 2011
Messages
60
Location
NSW
Gender
Male
HSC
2012
i know how to calculate the concentration of a single acid or base in a titrated mixture
but i want to know is how to find the concentration of the entire acid-base mixture together *

heres the sample qs that bugging me*
calculate the concentration of the mixture where*
500mL of 0.1M of HCl is mixed with 500mL of 0.05 M of NaOH*

Also is it possible to calculate the pH by subtracting the pH of the acid by the base*

or do u subtract the the concentration of the acid by the base and then using the pH formula to calculate the pH
 

RiFiPi

New Member
Joined
Apr 1, 2013
Messages
7
Gender
Undisclosed
HSC
2013
n = C.V (in litres)
Moles of HCl = 0.1 times 0.5 = 0.05 moles
Moles of NaOH = 0.05 times 0.5 = 0.025 moles

HCl will be in excess by 0.025 moles (HCl - NaOH)

This means there will be 0.025 moles of H+ ions left over (as opposed to left of OH- ions if the NaOH was in excess.)

The total volume of solution is now the combined volumes of each solution, i.e. 0.5L + 0.5L = 1L

We are now trying to find Conc of H+
C=n/V
C = 0.025/1
C (of H+ ions) = 0.025 M

pH = -log[H+]
= -log[0.025]
= 1.6

Hope that helped/I hope that's worked out right.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top